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Ramos-Espiritu L, Kleinboelting S, Navarrete FA, Alvau A, Visconti PE, Valsecchi F, Starkov A, Manfredi G, Buck H, Adura C, Zippin JH, van den Heuvel J, Glickman JF, Steegborn C, Levin LR, Buck J. Discovery of LRE1 as a specific and allosteric inhibitor of soluble adenylyl cyclase. Nat Chem Biol 2016; 12:838-44. [PMID: 27547922 PMCID: PMC5030147 DOI: 10.1038/nchembio.2151] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 05/23/2016] [Indexed: 12/22/2022]
Abstract
The prototypical second messenger cAMP regulates a wide variety of physiological processes. It can simultaneously mediate diverse functions by acting locally in independently regulated microdomains. In mammalian cells, two types of adenylyl cyclase generate cAMP: G-protein-regulated transmembrane adenylyl cyclases and bicarbonate-, calcium- and ATP-regulated soluble adenylyl cyclase (sAC). Because each type of cyclase regulates distinct microdomains, methods to distinguish between them are needed to understand cAMP signaling. We developed a mass-spectrometry-based adenylyl cyclase assay, which we used to identify a new sAC-specific inhibitor, LRE1. LRE1 bound to the bicarbonate activator binding site and inhibited sAC via a unique allosteric mechanism. LRE1 prevented sAC-dependent processes in cellular and physiological systems, and it will facilitate exploration of the therapeutic potential of sAC inhibition.
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Affiliation(s)
- Lavoisier Ramos-Espiritu
- Department of Pharmacology, Weill Cornell Medical College, New York, New York, USA
- The High-Throughput Screening and Spectroscopy Resource Center, The Rockefeller University, New York, New York, USA
| | | | - Felipe A Navarrete
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts, USA
| | - Antonio Alvau
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts, USA
| | - Pablo E Visconti
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts, USA
| | - Federica Valsecchi
- Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York, USA
| | - Anatoly Starkov
- Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York, USA
| | - Giovanni Manfredi
- Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York, USA
| | - Hannes Buck
- Department of Pharmacology, Weill Cornell Medical College, New York, New York, USA
| | - Carolina Adura
- The High-Throughput Screening and Spectroscopy Resource Center, The Rockefeller University, New York, New York, USA
| | - Jonathan H Zippin
- Department of Dermatology, Weill Cornell Medical College, New York, New York, USA
| | | | - J Fraser Glickman
- The High-Throughput Screening and Spectroscopy Resource Center, The Rockefeller University, New York, New York, USA
| | - Clemens Steegborn
- Department of Biochemistry, University of Bayreuth, Bayreuth, Germany
| | - Lonny R Levin
- Department of Pharmacology, Weill Cornell Medical College, New York, New York, USA
| | - Jochen Buck
- Department of Pharmacology, Weill Cornell Medical College, New York, New York, USA
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102
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Lionaki E, Gkikas I, Tavernarakis N. Differential Protein Distribution between the Nucleus and Mitochondria: Implications in Aging. Front Genet 2016; 7:162. [PMID: 27695477 PMCID: PMC5025450 DOI: 10.3389/fgene.2016.00162] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 09/01/2016] [Indexed: 01/05/2023] Open
Abstract
The coordination of nuclear and mitochondrial genomes plays a pivotal role in maintenance of mitochondrial biogenesis and functionality during stress and aging. Environmental and cellular inputs signal to nucleus and/or mitochondria to trigger interorganellar compensatory responses. Loss of this tightly orchestrated coordination results in loss of cellular homeostasis and underlies various pathologies and age-related diseases. Several signaling cascades that govern interorganellar communication have been revealed up to now, and have been classified as part of the anterograde (nucleus to mitochondria) or retrograde (mitochondrial to nucleus) response. Many of these molecular pathways rely on the dual distribution of nuclear or mitochondrial components under basal or stress conditions. These dually localized components usually engage in specific tasks in their primary organelle of function, whilst upon cellular stimuli, they appear in the other organelle where they engage in the same or a different task, triggering a compensatory stress response. In this review, we focus on protein factors distributed between the nucleus and mitochondria and activated to exert their functions upon basal or stress conditions. We further discuss implications of bi-organellar targeting in the context of aging.
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Affiliation(s)
- Eirini Lionaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas Heraklion, Greece
| | - Ilias Gkikas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas Heraklion, Greece
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-HellasHeraklion, Greece; Department of Basic Sciences, Faculty of Medicine, University of CreteHeraklion, Greece
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103
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Wilson CM, Roa JN, Cox GK, Tresguerres M, Farrell AP. Introducing a novel mechanism to control heart rate in the ancestral Pacific hagfish. ACTA ACUST UNITED AC 2016; 219:3227-3236. [PMID: 27510962 DOI: 10.1242/jeb.138198] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 08/02/2016] [Indexed: 12/15/2022]
Abstract
Although neural modulation of heart rate is well established among chordate animals, the Pacific hagfish (Eptatretus stoutii) lacks any cardiac innervation, yet it can increase its heart rate from the steady, depressed heart rate seen in prolonged anoxia to almost double its normal normoxic heart rate, an almost fourfold overall change during the 1-h recovery from anoxia. The present study sought mechanistic explanations for these regulatory changes in heart rate. We provide evidence for a bicarbonate-activated, soluble adenylyl cyclase (sAC)-dependent mechanism to control heart rate, a mechanism never previously implicated in chordate cardiac control.
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Affiliation(s)
- Christopher M Wilson
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada V6T 1Z4
| | - Jinae N Roa
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Georgina K Cox
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada V6T 1Z4
| | - Martin Tresguerres
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Anthony P Farrell
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada V6T 1Z4.,Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall, Vancouver, British Columbia, Canada V6T 1Z4
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104
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Chang J, Go S, de Waart DR, Munoz‐Garrido P, Beuers U, Paulusma CC, Oude Elferink R. Soluble Adenylyl Cyclase Regulates Bile Salt-Induced Apoptosis in Human Cholangiocytes. Hepatology 2016; 64:522-34. [PMID: 26991014 PMCID: PMC5111777 DOI: 10.1002/hep.28550] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 03/14/2016] [Indexed: 12/20/2022]
Abstract
UNLABELLED Anion exchanger 2 (AE2), the principal bicarbonate secretor in the human biliary tree, is down-regulated in primary biliary cholangitis. AE2 creates a "bicarbonate umbrella" that protects cholangiocytes from the proapoptotic effects of bile salts by maintaining them deprotonated. We observed that knockdown of AE2 sensitized immortalized H69 human cholangiocytes to not only bile salt-induced apoptosis (BSIA) but also etoposide-induced apoptosis. Because the toxicity of etoposide is pH-independent, there could be a more general mechanism for sensitization of AE2-depleted cholangiocytes to apoptotic stimuli. We found that AE2 deficiency led to intracellular bicarbonate accumulation and increased expression and activity of soluble adenylyl cyclase (sAC), an evolutionarily conserved bicarbonate sensor. Thus, we hypothesized that sAC regulates BSIA. H69 cholangiocytes and primary mouse cholangiocytes were used as models. The sAC-specific inhibitor KH7 not only reversed sensitization to BSIA in AE2-depleted H69 cholangiocytes but even completely prevented BSIA. sAC knockdown by tetracycline-inducible short hairpin RNA also prevented BSIA. In addition, sAC inhibition reversed BSIA membrane blebbing, nuclear condensation, and DNA fragmentation. Furthermore, sAC inhibition also prevented BSIA in primary mouse cholangiocytes. Mechanistically, sAC inhibition prevented Bax phosphorylation at Thr167 and mitochondrial translocation of Bax and cytochrome c release but not c-Jun N-terminal kinase activation during BSIA. Finally, BSIA in H69 cholangiocytes was inhibited by intracellular Ca(2+) chelation, aggravated by thapsigargin, and unaffected by removal of extracellular calcium. CONCLUSIONS BSIA is regulated by sAC, depends on intracellular Ca(2+) stores, and is mediated by the intrinsic apoptotic pathway; down-regulation of AE2 in primary biliary cholangitis sensitizes cholangiocytes to apoptotic insults by activating sAC, which may play a crucial role in disease pathogenesis. (Hepatology 2016;64:522-534).
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Affiliation(s)
- Jung‐Chin Chang
- Tytgat Institute for Liver and Intestinal Research, Academic Medical CenterUniversity of AmsterdamAmsterdamThe Netherlands
| | - Simei Go
- Tytgat Institute for Liver and Intestinal Research, Academic Medical CenterUniversity of AmsterdamAmsterdamThe Netherlands
| | - Dirk R. de Waart
- Tytgat Institute for Liver and Intestinal Research, Academic Medical CenterUniversity of AmsterdamAmsterdamThe Netherlands
| | - Patricia Munoz‐Garrido
- Tytgat Institute for Liver and Intestinal Research, Academic Medical CenterUniversity of AmsterdamAmsterdamThe Netherlands,Department of Liver and Gastrointestinal Diseases, Biodonostia Health Research Institute, Donostia University HospitalUniversity of the Basque Country (UPV/EHU)San SebastiánSpain,National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, Instituto de Salud Carlos III)MadridSpain
| | - Ulrich Beuers
- Tytgat Institute for Liver and Intestinal Research, Academic Medical CenterUniversity of AmsterdamAmsterdamThe Netherlands
| | - Coen C. Paulusma
- Tytgat Institute for Liver and Intestinal Research, Academic Medical CenterUniversity of AmsterdamAmsterdamThe Netherlands
| | - Ronald Oude Elferink
- Tytgat Institute for Liver and Intestinal Research, Academic Medical CenterUniversity of AmsterdamAmsterdamThe Netherlands
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105
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Inda C, Dos Santos Claro PA, Bonfiglio JJ, Senin SA, Maccarrone G, Turck CW, Silberstein S. Different cAMP sources are critically involved in G protein-coupled receptor CRHR1 signaling. J Cell Biol 2016; 214:181-95. [PMID: 27402953 PMCID: PMC4949449 DOI: 10.1083/jcb.201512075] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 06/10/2016] [Indexed: 02/07/2023] Open
Abstract
Corticotropin-releasing hormone receptor 1 (CRHR1) activates G protein-dependent and internalization-dependent signaling mechanisms. Here, we report that the cyclic AMP (cAMP) response of CRHR1 in physiologically relevant scenarios engages separate cAMP sources, involving the atypical soluble adenylyl cyclase (sAC) in addition to transmembrane adenylyl cyclases (tmACs). cAMP produced by tmACs and sAC is required for the acute phase of extracellular signal regulated kinase 1/2 activation triggered by CRH-stimulated CRHR1, but only sAC activity is essential for the sustained internalization-dependent phase. Thus, different cAMP sources are involved in different signaling mechanisms. Examination of the cAMP response revealed that CRH-activated CRHR1 generates cAMP after endocytosis. Characterizing CRHR1 signaling uncovered a specific link between CRH-activated CRHR1, sAC, and endosome-based signaling. We provide evidence of sAC being involved in an endocytosis-dependent cAMP response, strengthening the emerging model of GPCR signaling in which the cAMP response does not occur exclusively at the plasma membrane and introducing the notion of sAC as an alternative source of cAMP.
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Affiliation(s)
- Carolina Inda
- Instituto de Investigación en Biomedicina de Buenos Aires-CONICET-Partner Institute of the Max Planck Society, C1425FQD Buenos Aires, Argentina Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, C1428EHA Buenos Aires, Argentina
| | - Paula A Dos Santos Claro
- Instituto de Investigación en Biomedicina de Buenos Aires-CONICET-Partner Institute of the Max Planck Society, C1425FQD Buenos Aires, Argentina Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, C1428EHA Buenos Aires, Argentina
| | - Juan J Bonfiglio
- Instituto de Investigación en Biomedicina de Buenos Aires-CONICET-Partner Institute of the Max Planck Society, C1425FQD Buenos Aires, Argentina Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, C1428EHA Buenos Aires, Argentina
| | - Sergio A Senin
- Instituto de Investigación en Biomedicina de Buenos Aires-CONICET-Partner Institute of the Max Planck Society, C1425FQD Buenos Aires, Argentina
| | - Giuseppina Maccarrone
- Department of Translational Research in Psychiatry, Max Planck Institute of Psychiatry, 80804 Munich, Germany
| | - Christoph W Turck
- Department of Translational Research in Psychiatry, Max Planck Institute of Psychiatry, 80804 Munich, Germany
| | - Susana Silberstein
- Instituto de Investigación en Biomedicina de Buenos Aires-CONICET-Partner Institute of the Max Planck Society, C1425FQD Buenos Aires, Argentina Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, C1428EHA Buenos Aires, Argentina
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106
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Li X, Wang L, Li Y, Zhao N, Zhen L, Fu J, Yang Q. Calcium regulates motility and protein phosphorylation by changing cAMP and ATP concentrations in boar sperm in vitro. Anim Reprod Sci 2016; 172:39-51. [PMID: 27423488 DOI: 10.1016/j.anireprosci.2016.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/29/2016] [Accepted: 07/01/2016] [Indexed: 12/15/2022]
Abstract
Considering the importance of calcium (Ca(2+)) in regulating sperm capacitation, hyperactivation and acrosome reaction, little is known about the molecular mechanism of action of this ion in this process. In the present study, assessment of the molecular mechanism from the perspective of energy metabolism occurred. Sperm motility variables were determined using computer-assisted sperm analysis (CASA) and the phosphorylation of PKA substrates, tyrosine residues and AMP-activated protein kinase (AMPK) were analyzed by Western blot. Moreover, intracellular sperm-specific glyceraldehyde 3-phosphatedehydrogenase (GAPDH) activity, 3'-5'-cyclic adenosine monophosphate (cAMP) and adenosine 5'-triphosphate (ATP) concentrations were assessed in boar sperm treated with Ca(2+). Results of the present study indicated that, under greater extracellular Ca(2+)concentrations (≥3.0mM), sperm motility and protein phosphorylation were inhibited. Interestingly, these changes were correlated with that of GAPDH activity, AMPK phosphorylation, cAMP and ATP concentrations. The negative effects of Ca(2+) on these intracellular processes were attenuated by addition of the calmodulin (CaM) inhibitor W7 and the inhibitor of calmodulin-dependent protein kinase (CaMK), KN-93. In the presence of greater extracellular Ca(2+), however, the phosphorylation pathway was suppressed by H-89. Taken together, these results suggested that Ca(2+) had a dual role in regulating boar sperm motility and protein phosphorylation due to the changes of cAMP and ATP concentrations, in response to cAMP-mediated signal transduction and the Ca(2+) signaling cascade. The present study provided some novel insights into the molecular mechanism underlying the effects of Ca(2+) on boar sperm as well as the involvement of energy metabolism in this mechanism.
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Affiliation(s)
- Xinhong Li
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Lirui Wang
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yuhua Li
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Na Zhao
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Linqing Zhen
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jieli Fu
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qiangzhen Yang
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
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107
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Pancreatic Beta Cell G-Protein Coupled Receptors and Second Messenger Interactions: A Systems Biology Computational Analysis. PLoS One 2016; 11:e0152869. [PMID: 27138453 PMCID: PMC4854486 DOI: 10.1371/journal.pone.0152869] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 03/21/2016] [Indexed: 12/17/2022] Open
Abstract
Insulin secretory in pancreatic beta-cells responses to nutrient stimuli and hormonal modulators include multiple messengers and signaling pathways with complex interdependencies. Here we present a computational model that incorporates recent data on glucose metabolism, plasma membrane potential, G-protein-coupled-receptors (GPCR), cytoplasmic and endoplasmic reticulum calcium dynamics, cAMP and phospholipase C pathways that regulate interactions between second messengers in pancreatic beta-cells. The values of key model parameters were inferred from published experimental data. The model gives a reasonable fit to important aspects of experimentally measured metabolic and second messenger concentrations and provides a framework for analyzing the role of metabolic, hormones and neurotransmitters changes on insulin secretion. Our analysis of the dynamic data provides support for the hypothesis that activation of Ca2+-dependent adenylyl cyclases play a critical role in modulating the effects of glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and catecholamines. The regulatory properties of adenylyl cyclase isoforms determine fluctuations in cytoplasmic cAMP concentration and reveal a synergistic action of glucose, GLP-1 and GIP on insulin secretion. On the other hand, the regulatory properties of phospholipase C isoforms determine the interaction of glucose, acetylcholine and free fatty acids (FFA) (that act through the FFA receptors) on insulin secretion. We found that a combination of GPCR agonists activating different messenger pathways can stimulate insulin secretion more effectively than a combination of GPCR agonists for a single pathway. This analysis also suggests that the activators of GLP-1, GIP and FFA receptors may have a relatively low risk of hypoglycemia in fasting conditions whereas an activator of muscarinic receptors can increase this risk. This computational analysis demonstrates that study of second messenger pathway interactions will improve understanding of critical regulatory sites, how different GPCRs interact and pharmacological targets for modulating insulin secretion in type 2 diabetes.
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108
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Wang Z, Liu D, Varin A, Nicolas V, Courilleau D, Mateo P, Caubere C, Rouet P, Gomez AM, Vandecasteele G, Fischmeister R, Brenner C. A cardiac mitochondrial cAMP signaling pathway regulates calcium accumulation, permeability transition and cell death. Cell Death Dis 2016; 7:e2198. [PMID: 27100892 PMCID: PMC4855650 DOI: 10.1038/cddis.2016.106] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 03/17/2016] [Accepted: 03/21/2016] [Indexed: 12/19/2022]
Abstract
Although cardiac cytosolic cyclic 3',5'-adenosine monophosphate (cAMP) regulates multiple processes, such as beating, contractility, metabolism and apoptosis, little is known yet on the role of this second messenger within cardiac mitochondria. Using cellular and subcellular approaches, we demonstrate here the local expression of several actors of cAMP signaling within cardiac mitochondria, namely a truncated form of soluble AC (sACt) and the exchange protein directly activated by cAMP 1 (Epac1), and show a protective role for sACt against cell death, apoptosis as well as necrosis in primary cardiomyocytes. Upon stimulation with bicarbonate (HCO3(-)) and Ca(2+), sACt produces cAMP, which in turn stimulates oxygen consumption, increases the mitochondrial membrane potential (ΔΨm) and ATP production. cAMP is rate limiting for matrix Ca(2+) entry via Epac1 and the mitochondrial calcium uniporter and, as a consequence, prevents mitochondrial permeability transition (MPT). The mitochondrial cAMP effects involve neither protein kinase A, Epac2 nor the mitochondrial Na(+)/Ca(2+) exchanger. In addition, in mitochondria isolated from failing rat hearts, stimulation of the mitochondrial cAMP pathway by HCO3(-) rescued the sensitization of mitochondria to Ca(2+)-induced MPT. Thus, our study identifies a link between mitochondrial cAMP, mitochondrial metabolism and cell death in the heart, which is independent of cytosolic cAMP signaling. Our results might have implications for therapeutic prevention of cell death in cardiac pathologies.
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Affiliation(s)
- Z Wang
- INSERM UMR-S 1180, Faculté de Pharmacie, Université Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
| | - D Liu
- INSERM UMR-S 1180, Faculté de Pharmacie, Université Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
| | - A Varin
- INSERM UMR-S 1180, Faculté de Pharmacie, Université Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
| | - V Nicolas
- UMS–IPSIT, Université Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
| | - D Courilleau
- UMS–IPSIT, Université Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
| | - P Mateo
- INSERM UMR-S 1180, Faculté de Pharmacie, Université Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
| | - C Caubere
- INSERM I2MC, UMR 1048, Université Paul Sabatier, Toulouse, France
| | - P Rouet
- INSERM I2MC, UMR 1048, Université Paul Sabatier, Toulouse, France
| | - A-M Gomez
- INSERM UMR-S 1180, Faculté de Pharmacie, Université Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
| | - G Vandecasteele
- INSERM UMR-S 1180, Faculté de Pharmacie, Université Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
| | - R Fischmeister
- INSERM UMR-S 1180, Faculté de Pharmacie, Université Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
- UMS–IPSIT, Université Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
| | - C Brenner
- INSERM UMR-S 1180, Faculté de Pharmacie, Université Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
- UMS–IPSIT, Université Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
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109
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Modeling of glucose-induced cAMP oscillations in pancreatic β cells: cAMP rocks when metabolism rolls. Biophys J 2016. [PMID: 26200880 DOI: 10.1016/j.bpj.2015.06.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Recent advances in imaging technology have revealed oscillations of cyclic adenosine monophosphate (cAMP) in insulin-secreting cells. These oscillations may be in phase with cytosolic calcium oscillations or out of phase. cAMP oscillations have previously been modeled as driven by oscillations in calcium, based on the known dependence of the enzymes that generate cAMP (adenylyl cyclase) and degrade it (phosphodiesterase). However, cAMP oscillations have also been reported to occur in the absence of calcium oscillations. Motivated by similarities between the properties of cAMP and metabolic oscillations in pancreatic β cells, we propose here that in addition to direct control by calcium, cAMP is controlled by metabolism. Specifically, we hypothesize that AMP inhibits adenylyl cyclase. We incorporate this hypothesis into the dual oscillator model for β cells, in which metabolic (glycolytic) oscillations cooperate with modulation of ion channels and metabolism by calcium. We show that the combination of oscillations in AMP and calcium in the dual oscillator model can account for the diverse oscillatory patterns that have been observed, as well as for experimental perturbations of those patterns. Predictions to further test the model are provided.
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110
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Cd(2+) sensitivity and permeability of a low voltage-activated Ca(2+) channel with CatSper-like selectivity filter. Cell Calcium 2016; 60:41-50. [PMID: 27134080 DOI: 10.1016/j.ceca.2016.03.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 03/21/2016] [Accepted: 03/30/2016] [Indexed: 11/22/2022]
Abstract
CatSper is a sperm-specific Ca(2+) channel that plays an essential role in the male fertility. However, its biophysical properties have been poorly characterized mainly due to its deficient heterologous expression. As other voltage-gated Ca(2+) channels (CaVs), CatSper possesses a conserved Ca(2+)-selective filter motif ([T/S]x[D/E]xW) in the pore region. Interestingly, CatSper conserves four aspartic acids (DDDD) as the negatively charged residues in this motif while high voltage-activated CaVs have four glutamic acids (EEEE) and low voltage-activated CaVs possess two glutamic acids and two aspartic acids (EEDD). Previous studies based on site-directed mutagenesis of L- and T-type channels showed that the number of D seems to have a negative correlation with their cadmium (Cd(2+)) sensitivity. These results suggest that CatSper (DDDD) would have low sensitivity to Cd(2+). To explore Cd(2+)-sensitivity and -permeability of CatSper, we performed two types of experiments: 1) Electrophysiological analysis of heterologously expressed human CaV3.1 channel and three pore mutants (DEDD, EDDD and DDDD), 2) Cd(2+) imaging of human spermatozoa with FluoZin-1. Electrophysiological studies showed a significant increase in Cd(2+) and manganese (Mn(2+)) currents through the CaV3.1 mutants as well as a reduction in the inhibitory effect of Cd(2+) on the Ca(2+) current. In fluorescence imaging with human sperm, we observed an increase in Cd(2+) influx potentiated by progesterone, a potent activator of CatSper. These results support our hypothesis, namely that Cd(2+)-sensitivity and -permeability are related to the absolute number of D in the Ca(2+)-selective filter independently to the type of the Cav channels.
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111
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Mukherjee S, Jansen V, Jikeli JF, Hamzeh H, Alvarez L, Dombrowski M, Balbach M, Strünker T, Seifert R, Kaupp UB, Wachten D. A novel biosensor to study cAMP dynamics in cilia and flagella. eLife 2016; 5. [PMID: 27003291 PMCID: PMC4811770 DOI: 10.7554/elife.14052] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 03/05/2016] [Indexed: 01/09/2023] Open
Abstract
The cellular messenger cAMP regulates multiple cellular functions, including signaling in cilia and flagella. The cAMP dynamics in these subcellular compartments are ill-defined. We introduce a novel FRET-based cAMP biosensor with nanomolar sensitivity that is out of reach for other sensors. To measure cAMP dynamics in the sperm flagellum, we generated transgenic mice and reveal that the hitherto methods determining total cAMP levels do not reflect changes in free cAMP levels. Moreover, cAMP dynamics in the midpiece and principal piece of the flagellum are distinctively different. The sole cAMP source in the flagellum is the soluble adenylate cyclase (SACY). Although bicarbonate-dependent SACY activity requires Ca2+, basal SACY activity is suppressed by Ca2+. Finally, we also applied the sensor to primary cilia. Our new cAMP biosensor features unique characteristics that allow gaining new insights into cAMP signaling and unravel the molecular mechanisms underlying ciliary function in vitro and in vivo. DOI:http://dx.doi.org/10.7554/eLife.14052.001 Cells can change the way they grow, move or develop in response to information from their environment. This information is first detected at the surface of the cell and then the information is relayed around the interior of the cell by signaling molecules known as “second messengers”. A molecule called cAMP is a well-known second messenger that is involved in many different signaling pathways. Therefore, the levels of cAMP in specific areas of the cell need to be precisely regulated to enable different signaling pathways to be activated at specific times and locations. Some cells have hair-like structures called cilia or flagella on their surface. Cilia and flagella are able to move the fluid that surrounds the cells or even move the cells themselves. The second messenger cAMP plays an essential role in making cilia move, but it is challenging to analyze the dynamics of cAMP – that this, how the levels of this molecule change over time – in these structures. The levels of cAMP in live cells can only be measured using fluorescent biosensors. Introducing these biosensors into specific cell structures is difficult and they are not sensitive enough to respond to low levels of cAMP. Furthermore, it is difficult to measure cAMP activity inside such tiny structures using these biosensors. Mukherjee, Jansen, Jikeli et al. now address some of these challenges by creating a new cAMP biosensor that has several unique features. Most importantly, it can respond to very low levels of cAMP, making it more sensitive than previous biosensors. Mukherjee et al. test this new biosensor in the flagella of sperm cells from mice, which reveals how the production of cAMP is regulated in the flagellum. The new biosensor also shows that different parts of the flagellum can have different cAMP dynamics. In the future, this new biosensor could be used to study cAMP in other structures and compartments within cells. DOI:http://dx.doi.org/10.7554/eLife.14052.002
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Affiliation(s)
- Shatanik Mukherjee
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research, Bonn, Germany
| | - Vera Jansen
- Minerva Max Planck Research Group, Molecular Physiology, Center of Advanced European Studies and Research, Bonn, Germany
| | - Jan F Jikeli
- Minerva Max Planck Research Group, Molecular Physiology, Center of Advanced European Studies and Research, Bonn, Germany
| | - Hussein Hamzeh
- Minerva Max Planck Research Group, Molecular Physiology, Center of Advanced European Studies and Research, Bonn, Germany
| | - Luis Alvarez
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research, Bonn, Germany
| | - Marco Dombrowski
- Minerva Max Planck Research Group, Molecular Physiology, Center of Advanced European Studies and Research, Bonn, Germany
| | - Melanie Balbach
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research, Bonn, Germany
| | - Timo Strünker
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research, Bonn, Germany.,Centrum für Reproduktionsmedizin und Andrologie, Universitätsklinikum Münster, Münster, Germany
| | - Reinhard Seifert
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research, Bonn, Germany
| | - U Benjamin Kaupp
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research, Bonn, Germany
| | - Dagmar Wachten
- Minerva Max Planck Research Group, Molecular Physiology, Center of Advanced European Studies and Research, Bonn, Germany
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112
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Kleinboelting S, Ramos-Espiritu L, Buck H, Colis L, van den Heuvel J, Glickman JF, Levin LR, Buck J, Steegborn C. Bithionol Potently Inhibits Human Soluble Adenylyl Cyclase through Binding to the Allosteric Activator Site. J Biol Chem 2016; 291:9776-84. [PMID: 26961873 DOI: 10.1074/jbc.m115.708255] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Indexed: 12/20/2022] Open
Abstract
The signaling molecule cAMP regulates functions ranging from bacterial transcription to mammalian memory. In mammals, cAMP is synthesized by nine transmembrane adenylyl cyclases (ACs) and one soluble AC (sAC). Despite similarities in their catalytic domains, these ACs differ in regulation. Transmembrane ACs respond to G proteins, whereas sAC is uniquely activated by bicarbonate. Via bicarbonate regulation, sAC acts as a physiological sensor for pH/bicarbonate/CO2, and it has been implicated as a therapeutic target, e.g. for diabetes, glaucoma, and a male contraceptive. Here we identify the bisphenols bithionol and hexachlorophene as potent, sAC-specific inhibitors. Inhibition appears mostly non-competitive with the substrate ATP, indicating that they act via an allosteric site. To analyze the interaction details, we solved a crystal structure of an sAC·bithionol complex. The structure reveals that the compounds are selective for sAC because they bind to the sAC-specific, allosteric binding site for the physiological activator bicarbonate. Structural comparison of the bithionol complex with apo-sAC and other sAC·ligand complexes along with mutagenesis experiments reveals an allosteric mechanism of inhibition; the compound induces rearrangements of substrate binding residues and of Arg(176), a trigger between the active site and allosteric site. Our results thus provide 1) novel insights into the communication between allosteric regulatory and active sites, 2) a novel mechanism for sAC inhibition, and 3) pharmacological compounds targeting this allosteric site and utilizing this mode of inhibition. These studies provide support for the future development of sAC-modulating drugs.
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Affiliation(s)
- Silke Kleinboelting
- From the Department of Biochemistry, University of Bayreuth, 95440 Bayreuth, Germany
| | - Lavoisier Ramos-Espiritu
- Department of Pharmacology, Weill Cornell Medical College, New York, New York 10065, High Throughput Screening and Spectroscopy Resource Center, The Rockefeller University, New York, New York 10065, and
| | - Hannes Buck
- Department of Pharmacology, Weill Cornell Medical College, New York, New York 10065
| | - Laureen Colis
- Department of Pharmacology, Weill Cornell Medical College, New York, New York 10065
| | | | - J Fraser Glickman
- High Throughput Screening and Spectroscopy Resource Center, The Rockefeller University, New York, New York 10065, and
| | - Lonny R Levin
- Department of Pharmacology, Weill Cornell Medical College, New York, New York 10065
| | - Jochen Buck
- Department of Pharmacology, Weill Cornell Medical College, New York, New York 10065
| | - Clemens Steegborn
- From the Department of Biochemistry, University of Bayreuth, 95440 Bayreuth, Germany,
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113
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De Rasmo D, Micelli L, Santeramo A, Signorile A, Lattanzio P, Papa S. cAMP regulates the functional activity, coupling efficiency and structural organization of mammalian FOF1 ATP synthase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:350-8. [PMID: 26775111 DOI: 10.1016/j.bbabio.2016.01.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 12/30/2015] [Accepted: 01/05/2016] [Indexed: 01/18/2023]
Abstract
The present study shows that in isolated mitochondria and myoblast cultures depletion of cAMP, induced by sAC inhibition, depresses both ATP synthesis and hydrolysis by the FOF1 ATP synthase (complex V) of the oxidative phosphorylation system (OXPHOS). These effects are accompanied by the decrease of the respiratory membrane potential, decreased level of FOF1 connecting subunits and depressed oligomerization of the complex. All these effects of sAC inhibition are prevented by the addition of the membrane-permeant 8-Br-cAMP. These results show, for the first time, that cAMP promotes ATP production by complex V and prevents, at the same time, its detour to a mitochondrial membrane leak conductance, which is involved in cell death.
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Affiliation(s)
- Domenico De Rasmo
- Institute of Biomembrane and Bioenergetics, National Research Council, Bari 70124, Italy.
| | - Loris Micelli
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro", Bari 70124, Italy
| | - Arcangela Santeramo
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro", Bari 70124, Italy
| | - Anna Signorile
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro", Bari 70124, Italy
| | - Paolo Lattanzio
- Institute of Biomembrane and Bioenergetics, National Research Council, Bari 70124, Italy
| | - Sergio Papa
- Institute of Biomembrane and Bioenergetics, National Research Council, Bari 70124, Italy; Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro", Bari 70124, Italy
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114
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Davies TG, Jhoti H, Pathuri P, Williams G. Selecting the Right Targets for Fragment-Based Drug Discovery. FRAGMENT-BASED DRUG DISCOVERY LESSONS AND OUTLOOK 2016. [DOI: 10.1002/9783527683604.ch02] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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115
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Spät A, Hunyady L, Szanda G. Signaling Interactions in the Adrenal Cortex. Front Endocrinol (Lausanne) 2016; 7:17. [PMID: 26973596 PMCID: PMC4770035 DOI: 10.3389/fendo.2016.00017] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 02/11/2016] [Indexed: 11/30/2022] Open
Abstract
The major physiological stimuli of aldosterone secretion are angiotensin II (AII) and extracellular K(+), whereas cortisol production is primarily regulated by corticotropin (ACTH) in fasciculata cells. AII triggers Ca(2+) release from internal stores that is followed by store-operated and voltage-dependent Ca(2+) entry, whereas K(+)-evoked depolarization activates voltage-dependent Ca(2+) channels. ACTH acts primarily through the formation of cAMP and subsequent protein phosphorylation by protein kinase A. Both Ca(2+) and cAMP facilitate the transfer of cholesterol to mitochondrial inner membrane. The cytosolic Ca(2+) signal is transferred into the mitochondrial matrix and enhances pyridine nucleotide reduction. Increased formation of NADH results in increased ATP production, whereas that of NADPH supports steroid production. In reality, the control of adrenocortical function is a lot more sophisticated with second messengers crosstalking and mutually modifying each other's pathways. Cytosolic Ca(2+) and cGMP are both capable of modifying cAMP metabolism, while cAMP may enhance Ca(2+) release and voltage-activated Ca(2+) channel activity. Besides, mitochondrial Ca(2+) signal brings about cAMP formation within the organelle and this further enhances aldosterone production. Maintained aldosterone and cortisol secretion are optimized by the concurrent actions of Ca(2+) and cAMP, as exemplified by the apparent synergism of Ca(2+) influx (inducing cAMP formation) and Ca(2+) release during response to AII. Thus, cross-actions of parallel signal transducing pathways are not mere intracellular curiosities but rather substantial phenomena, which fine-tune the biological response. Our review focuses on these functionally relevant interactions between the Ca(2+) and the cyclic nucleotide signal transducing pathways hitherto described in the adrenal cortex.
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Affiliation(s)
- András Spät
- Department of Physiology, Semmelweis University Medical School, Budapest, Hungary
- Laboratory of Molecular Physiology, Hungarian Academy of Sciences, Budapest, Hungary
- *Correspondence: András Spät,
| | - László Hunyady
- Department of Physiology, Semmelweis University Medical School, Budapest, Hungary
- Laboratory of Molecular Physiology, Hungarian Academy of Sciences, Budapest, Hungary
| | - Gergő Szanda
- Department of Physiology, Semmelweis University Medical School, Budapest, Hungary
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116
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Boitseva EN, Denisenko VY, Kuz’mina TI. Evaluation of indicators of postejaculation maturation of spermatozoa of Bos taurus using a chlortetracycline test. Russ J Dev Biol 2015. [DOI: 10.1134/s1062360415060028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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117
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Lark DS, Reese LR, Ryan TE, Torres MJ, Smith CD, Lin CT, Neufer PD. Protein Kinase A Governs Oxidative Phosphorylation Kinetics and Oxidant Emitting Potential at Complex I. Front Physiol 2015; 6:332. [PMID: 26635618 PMCID: PMC4646981 DOI: 10.3389/fphys.2015.00332] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 11/02/2015] [Indexed: 11/24/2022] Open
Abstract
The mitochondrial electron transport system (ETS) is responsible for setting and maintaining both the energy and redox charges throughout the cell. Reversible phosphorylation of mitochondrial proteins, particularly via the soluble adenylyl cyclase (sAC)/cyclic AMP (cAMP)/Protein kinase A (PKA) axis, has recently been revealed as a potential mechanism regulating the ETS. However, the governance of cAMP/PKA signaling and its implications on ETS function are incompletely understood. In contrast to prior reports using exogenous bicarbonate, we provide evidence that endogenous CO2 produced by increased tricarboxylic acid (TCA) cycle flux is insufficient to increase mitochondrial cAMP levels, and that exogenous addition of membrane permeant 8Br-cAMP does not enhance mitochondrial respiratory capacity. We also report important non-specific effects of commonly used inhibitors of sAC which preclude their use in studies of mitochondrial function. In isolated liver mitochondria, inhibition of PKA reduced complex I-, but not complex II-supported respiratory capacity. In permeabilized myofibers, inhibition of PKA lowered both the Km and Vmax for complex I-supported respiration as well as succinate-supported H2O2 emitting potential. In summary, the data provided here improve our understanding of how mitochondrial cAMP production is regulated, illustrate a need for better tools to examine the impact of sAC activity on mitochondrial biology, and suggest that cAMP/PKA signaling contributes to the governance of electron flow through complex I of the ETS.
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Affiliation(s)
- Daniel S Lark
- East Carolina Diabetes and Obesity Institute Greenville, NC, USA ; Department of Kinesiology, East Carolina University Greenville, NC, USA
| | - Lauren R Reese
- East Carolina Diabetes and Obesity Institute Greenville, NC, USA ; Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - Terence E Ryan
- East Carolina Diabetes and Obesity Institute Greenville, NC, USA ; Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - Maria J Torres
- East Carolina Diabetes and Obesity Institute Greenville, NC, USA ; Department of Kinesiology, East Carolina University Greenville, NC, USA
| | - Cody D Smith
- East Carolina Diabetes and Obesity Institute Greenville, NC, USA ; Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - Chien-Te Lin
- East Carolina Diabetes and Obesity Institute Greenville, NC, USA ; Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - P Darrell Neufer
- East Carolina Diabetes and Obesity Institute Greenville, NC, USA ; Department of Kinesiology, East Carolina University Greenville, NC, USA ; Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA
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118
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Wandernoth PM, Mannowetz N, Szczyrba J, Grannemann L, Wolf A, Becker HM, Sly WS, Wennemuth G. Normal Fertility Requires the Expression of Carbonic Anhydrases II and IV in Sperm. J Biol Chem 2015; 290:29202-16. [PMID: 26487715 PMCID: PMC4705926 DOI: 10.1074/jbc.m115.698597] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Indexed: 12/20/2022] Open
Abstract
HCO3 (-) is a key factor in the regulation of sperm motility. High concentrations of HCO3 (-) in the female genital tract induce an increase in sperm beat frequency, which speeds progress of the sperm through the female reproductive tract. Carbonic anhydrases (CA), which catalyze the reversible hydration of CO2 to HCO3 (-), represent potential candidates in the regulation of the HCO3 (-) homeostasis in sperm and the composition of the male and female genital tract fluids. We show that two CA isoforms, CAII and CAIV, are distributed along the epididymal epithelium and appear with the onset of puberty. Expression analyses reveal an up-regulation of CAII and CAIV in the different epididymal sections of the knockout lines. In sperm, we find that CAII is located in the principal piece, whereas CAIV is present in the plasma membrane of the entire sperm tail. CAII and CAIV single knockout animals display an imbalanced HCO3 (-) homeostasis, resulting in substantially reduced sperm motility, swimming speed, and HCO3 (-)-enhanced beat frequency. The CA activity remaining in the sperm of CAII- and CAIV-null mutants is 35% and 68% of that found in WT mice. Sperm of the double knockout mutant mice show responses to stimulus by HCO3 (-) or CO2 that were delayed in onset and reduced in magnitude. In comparison with sperm from CAII and CAIV double knockout animals, pharmacological loss of CAIV in sperm from CAII knockout animals, show an even lower response to HCO3 (-). These results suggest that CAII and CAIV are required for optimal fertilization.
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Affiliation(s)
- Petra M Wandernoth
- From the Institute of Anatomy, University Hospital, University Duisburg-Essen, Hufelandstraße 55, 45122 Essen, Germany
| | - Nadja Mannowetz
- From the Institute of Anatomy, University Hospital, University Duisburg-Essen, Hufelandstraße 55, 45122 Essen, Germany
| | - Jaroslaw Szczyrba
- From the Institute of Anatomy, University Hospital, University Duisburg-Essen, Hufelandstraße 55, 45122 Essen, Germany
| | - Laura Grannemann
- From the Institute of Anatomy, University Hospital, University Duisburg-Essen, Hufelandstraße 55, 45122 Essen, Germany
| | - Anne Wolf
- the Department of Internal Medicine I, Saarland University Medical Center, Kirrberger Straße, 66421 Homburg/Saar, Germany
| | - Holger M Becker
- the Division of Zoology/Membrane Transport, Department of Biology, University of Kaiserslautern, Erwin-Schrödinger-Straße 13, 67663 Kaiserslautern, Germany, and
| | - William S Sly
- the Edward A. Doisy Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, Missouri 63104
| | - Gunther Wennemuth
- From the Institute of Anatomy, University Hospital, University Duisburg-Essen, Hufelandstraße 55, 45122 Essen, Germany,
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119
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Katona D, Rajki A, Di Benedetto G, Pozzan T, Spät A. Calcium-dependent mitochondrial cAMP production enhances aldosterone secretion. Mol Cell Endocrinol 2015; 412:196-204. [PMID: 25958040 DOI: 10.1016/j.mce.2015.05.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 04/27/2015] [Accepted: 05/03/2015] [Indexed: 10/23/2022]
Abstract
Glomerulosa cells secrete aldosterone in response to agonists coupled to Ca(2+) increases such as angiotensin II and corticotrophin, coupled to a cAMP dependent pathway. A recently recognized interaction between Ca(2+) and cAMP is the Ca(2+)-induced cAMP formation in the mitochondrial matrix. Here we describe that soluble adenylyl cyclase (sAC) is expressed in H295R adrenocortical cells. Mitochondrial cAMP formation, monitored with a mitochondria-targeted fluorescent sensor (4mtH30), is enhanced by HCO3(-) and the Ca(2+) mobilizing agonist angiotensin II. The effect of angiotensin II is inhibited by 2-OHE, an inhibitor of sAC, and by RNA interference of sAC, but enhanced by an inhibitor of phosphodiesterase PDE2A. Heterologous expression of the Ca(2+) binding protein S100G within the mitochondrial matrix attenuates angiotensin II-induced mitochondrial cAMP formation. Inhibition and knockdown of sAC significantly reduce angiotensin II-induced aldosterone production. These data provide the first evidence for a cell-specific functional role of mitochondrial cAMP.
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Affiliation(s)
- Dávid Katona
- Department of Physiology, Semmelweis University Medical School, Budapest, Hungary
| | - Anikó Rajki
- Laboratory of Molecular Physiology, Hungarian Academy of Sciences, Budapest, Hungary
| | - Giulietta Di Benedetto
- Institute of Neuroscience, Italian National Research Council, Padova, Italy; Venetian Institute of Molecular Medicine, Padova, Italy
| | - Tullio Pozzan
- Institute of Neuroscience, Italian National Research Council, Padova, Italy; Venetian Institute of Molecular Medicine, Padova, Italy
| | - András Spät
- Department of Physiology, Semmelweis University Medical School, Budapest, Hungary.
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120
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Wilderman A, Guo Y, Divakaruni AS, Perkins G, Zhang L, Murphy AN, Taylor SS, Insel PA. Proteomic and Metabolic Analyses of S49 Lymphoma Cells Reveal Novel Regulation of Mitochondria by cAMP and Protein Kinase A. J Biol Chem 2015. [PMID: 26203188 DOI: 10.1074/jbc.m115.658153] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclic AMP (cAMP), acting via protein kinase A (PKA), regulates many cellular responses, but the role of mitochondria in such responses is poorly understood. To define such roles, we used quantitative proteomic analysis of mitochondria-enriched fractions and performed functional and morphologic studies of wild-type (WT) and kin(-) (PKA-null) murine S49 lymphoma cells. Basally, 75 proteins significantly differed in abundance between WT and kin(-) S49 cells. WT, but not kin(-), S49 cells incubated with the cAMP analog 8-(4-chlorophenylthio)adenosine cAMP (CPT-cAMP) for 16 h have (a) increased expression of mitochondria-related genes and proteins, including ones in pathways of branched-chain amino acid and fatty acid metabolism and (b) increased maximal capacity of respiration on branched-chain keto acids and fatty acids. CPT-cAMP also regulates the cellular rate of ATP-utilization, as the rates of both ATP-linked respiration and proton efflux are decreased in WT but not kin(-) cells. CPT-cAMP protected WT S49 cells from glucose or glutamine deprivation, In contrast, CPT-cAMP did not protect kin(-) cells or WT cells treated with the PKA inhibitor H89 from glutamine deprivation. Under basal conditions, the mitochondrial structure of WT and kin(-) S49 cells is similar. Treatment with CPT-cAMP produced apoptotic changes (i.e. decreased mitochondrial density and size and loss of cristae) in WT, but not kin(-) cells. Together, these findings show that cAMP acts via PKA to regulate multiple aspects of mitochondrial function and structure. Mitochondrial perturbation thus likely contributes to cAMP/PKA-mediated cellular responses.
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Affiliation(s)
- Andrea Wilderman
- From the Department of Pharmacology, University of California San Diego, La Jolla, California 92093-0626
| | - Yurong Guo
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0654
| | - Ajit S Divakaruni
- From the Department of Pharmacology, University of California San Diego, La Jolla, California 92093-0626
| | - Guy Perkins
- National Center for Microscopy and Imaging Research, University of California San Diego, La Jolla, California 92093-0608, and
| | - Lingzhi Zhang
- From the Department of Pharmacology, University of California San Diego, La Jolla, California 92093-0626
| | - Anne N Murphy
- From the Department of Pharmacology, University of California San Diego, La Jolla, California 92093-0626
| | - Susan S Taylor
- From the Department of Pharmacology, University of California San Diego, La Jolla, California 92093-0626, Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093-0654
| | - Paul A Insel
- From the Department of Pharmacology, University of California San Diego, La Jolla, California 92093-0626, Department of Medicine, University of California San Diego, La Jolla, California 92093
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121
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Navarrete FA, García-Vázquez FA, Alvau A, Escoffier J, Krapf D, Sánchez-Cárdenas C, Salicioni AM, Darszon A, Visconti PE. Biphasic role of calcium in mouse sperm capacitation signaling pathways. J Cell Physiol 2015; 230:1758-1769. [PMID: 25597298 DOI: 10.1002/jcp.24873] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 11/19/2014] [Indexed: 12/18/2022]
Abstract
Mammalian sperm acquire fertilizing ability in the female tract in a process known as capacitation. At the molecular level, capacitation is associated with up-regulation of a cAMP-dependent pathway, changes in intracellular pH, intracellular Ca(2+), and an increase in tyrosine phosphorylation. How these signaling systems interact during capacitation is not well understood. Results presented in this study indicate that Ca(2+) ions have a biphasic role in the regulation of cAMP-dependent signaling. Media without added Ca(2+) salts (nominal zero Ca(2+)) still contain micromolar concentrations of this ion. Sperm incubated in this medium did not undergo PKA activation or the increase in tyrosine phosphorylation suggesting that these phosphorylation pathways require Ca(2+). However, chelation of the extracellular Ca(2+) traces by EGTA induced both cAMP-dependent phosphorylation and the increase in tyrosine phosphorylation. The EGTA effect in nominal zero Ca(2+) media was mimicked by two calmodulin antagonists, W7 and calmidazolium, and by the calcineurin inhibitor cyclosporine A. These results suggest that Ca(2+) ions regulate sperm cAMP and tyrosine phosphorylation pathways in a biphasic manner and that some of its effects are mediated by calmodulin. Interestingly, contrary to wild-type mouse sperm, sperm from CatSper1 KO mice underwent PKA activation and an increase in tyrosine phosphorylation upon incubation in nominal zero Ca(2+) media. Therefore, sperm lacking Catsper Ca(2+) channels behave as wild-type sperm incubated in the presence of EGTA. This latter result suggests that Catsper transports the Ca(2+) involved in the regulation of cAMP-dependent and tyrosine phosphorylation pathways required for sperm capacitation.
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Affiliation(s)
- Felipe A Navarrete
- Department of Veterinary and Animal Science, Integrated Sciences Building, University of Massachusetts, Amherst MA, USA
| | - Francisco A García-Vázquez
- Department of Veterinary and Animal Science, Integrated Sciences Building, University of Massachusetts, Amherst MA, USA.,Department of Physiology, Veterinary School, University of Murcia, Murcia, Spain.,International Excellence Campus for Higher Education and Research (Campus Mare Nostrum) and Institute for Biomedical Research of Murcia, Murcia, Spain
| | - Antonio Alvau
- Department of Veterinary and Animal Science, Integrated Sciences Building, University of Massachusetts, Amherst MA, USA
| | - Jessica Escoffier
- Department of Veterinary and Animal Science, Integrated Sciences Building, University of Massachusetts, Amherst MA, USA
| | - Dario Krapf
- Instituto de Biología Celular y Molecular de Rosario (CONICET), UNR, Buenos Aires, Argentina
| | | | - Ana M Salicioni
- Department of Veterinary and Animal Science, Integrated Sciences Building, University of Massachusetts, Amherst MA, USA
| | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, IBT-UNAM, Cuernavaca, México
| | - Pablo E Visconti
- Department of Veterinary and Animal Science, Integrated Sciences Building, University of Massachusetts, Amherst MA, USA
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122
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Roy J, Sen Santara S, Adhikari A, Mukherjee A, Adak S. Control of catalysis in globin coupled adenylate cyclase by a globin-B domain. Arch Biochem Biophys 2015; 579:85-90. [PMID: 26095616 DOI: 10.1016/j.abb.2015.06.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 06/08/2015] [Accepted: 06/09/2015] [Indexed: 10/23/2022]
Abstract
The globin coupled heme containing adenylate cyclase from Leishmania major (HemAC-Lm) has two globin domains (globin-A and globin-B). Globin-B domain (210-360 amino acids) may guide the interaction between globin-A and adenylate cyclase domains for the regulation of catalysis. We investigated the role of globin-B domain in HemAC-Lm by constructing a series of mutants namely Δ209 (209 amino acids deleted), Δ360 (360 amino acids deleted), H161A, H311A and H311A-Δ209. Spectroscopic data suggest that the Δ209 and H311A-Δ209 proteins to be Fe(2+)-O2 form and apo form, respectively, indicating that His311 residue in the globin-B domain is crucial for heme binding in Δ209 protein. However, the H311A mutant is still of the Fe(2+)-O2 form whereas H161A mutant shows the apo form, indicating that only His161 residue in the globin-A domain is responsible for heme binding in full length enzyme. cAMP measurements suggest that the activities of Δ360 and Δ209 proteins were ∼10 and ∼1000 times lesser than full length enzyme, respectively, leading to the fact that globin-B domain inhibited catalysis rather than activation in absence of globin-A domain. These data suggest that the O2 bound globin-A domain in HemAC-Lm allows the best cooperation of the catalytic domain interactions to generate optimum cAMP.
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Affiliation(s)
- Jayasree Roy
- Division of Structural Biology and Bio-informatics, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata 700 032, India
| | - Sumit Sen Santara
- Division of Structural Biology and Bio-informatics, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata 700 032, India
| | - Ayan Adhikari
- Division of Structural Biology and Bio-informatics, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata 700 032, India
| | - Aditi Mukherjee
- Division of Structural Biology and Bio-informatics, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata 700 032, India
| | - Subrata Adak
- Division of Structural Biology and Bio-informatics, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata 700 032, India.
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Covian R, French S, Kusnetz H, Balaban RS. Stimulation of oxidative phosphorylation by calcium in cardiac mitochondria is not influenced by cAMP and PKA activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1837:1913-1921. [PMID: 25178840 DOI: 10.1016/j.bbabio.2014.08.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 08/21/2014] [Accepted: 08/23/2014] [Indexed: 12/31/2022]
Abstract
Cardiac oxidative ATP generation is finely tuned to match several-fold increases in energy demand. Calcium has been proposed to play a role in the activation of ATP production via PKA phosphorylation in response to intramitochondrial cAMP generation. We evaluated the effect of cAMP, its membrane permeable analogs (dibutyryl-cAMP, 8-bromo-cAMP), and the PKA inhibitor H89 on respiration of isolated pig heart mitochondria. cAMP analogs did not stimulate State 3 respiration of Ca2 +-depleted mitochondria (82.2 ± 3.6% of control), in contrast to the 2-fold activation induced by 0.95 μM free Ca2 +, which was unaffected by H89. Using fluorescence and integrating sphere spectroscopy, we determined that Ca2 + increased the reduction of NADH (8%), and of cytochromes bH (3%), c1 (3%), c (4%), and a (2%), together with a doubling of conductances for Complex I + III and Complex IV. None of these changes were induced by cAMP analogs nor abolished by H89. In Ca2 +-undepleted mitochondria, we observed only slight changes in State 3 respiration rates upon addition of 50 μM cAMP (85 ± 9.9%), dibutyryl-cAMP (80.1 ± 5.2%), 8-bromo-cAMP (88.6 ± 3.3%), or 1 μM H89 (89.7 ± 19.9%) with respect to controls. Similar results were obtained when measuring respiration in heart homogenates. Addition of exogenous PKA with dibutyryl-cAMP or the constitutively active catalytic subunit of PKA to isolated mitochondria decreased State 3 respiration by only 5–15%. These functional studies suggest that alterations in mitochondrial cAMP and PKA activity do not contribute significantly to the acute Ca2 + stimulation of oxidative phosphorylation
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Affiliation(s)
- Raul Covian
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, 10 Center Dr, Room B1D416, Bethesda, MD 20892, USA.
| | - Stephanie French
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, 10 Center Dr, Room B1D416, Bethesda, MD 20892, USA
| | - Heather Kusnetz
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, 10 Center Dr, Room B1D416, Bethesda, MD 20892, USA
| | - Robert S Balaban
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, 10 Center Dr, Room B1D416, Bethesda, MD 20892, USA
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Barathy DV, Bharambe NG, Syed W, Zaveri A, Visweswariah SS, Colaςo M, Misquith S, Suguna K. Autoinhibitory mechanism and activity-related structural changes in a mycobacterial adenylyl cyclase. J Struct Biol 2015; 190:304-13. [PMID: 25916753 DOI: 10.1016/j.jsb.2015.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 04/15/2015] [Accepted: 04/20/2015] [Indexed: 01/02/2023]
Abstract
An adenylyl cyclase from Mycobacterium avium, Ma1120, is a functional orthologue of a pseudogene Rv1120c from Mycobacterium tuberculosis. We report the crystal structure of Ma1120 in a monomeric form and its truncated construct as a dimer. Ma1120 exists as a monomer in solution and crystallized as a monomer in the absence of substrate or inhibitor. An additional α-helix present at the N-terminus of the monomeric structure blocks the active site by interacting with the substrate binding residues and occupying the dimer interface region. However, the enzyme has been found to be active in solution, indicating the movement of the helix away from the interface to facilitate the formation of active dimers in conditions favourable for catalysis. Thus, the N-terminal helix of Ma1120 keeps the enzyme in an autoinhibited state when it is not active. Deletion of this helix enabled us to crystallize the molecule as an active homodimer in the presence of a P-site inhibitor 2',5'-dideoxy-3'-ATP, or pyrophosphate along with metal ions. The substrate specifying lysine residue plays a dual role of interacting with the substrate and stabilizing the dimer. The dimerization loop region harbouring the second substrate specifying residue, an aspartate, shows significant differences in conformation and position between the monomeric and dimeric structures. Thus, this study has not only revealed that significant structural transitions are required for the interconversion of the inactive and the active forms of the enzyme, but also provided precise nature of these transitions.
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Affiliation(s)
| | - Nikhil G Bharambe
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Wajeed Syed
- Department of Chemistry, St. Joseph's College, Bangalore 560 027, India
| | - Anisha Zaveri
- Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560 012, India
| | - Sandhya S Visweswariah
- Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore 560 012, India
| | - Melwin Colaςo
- Department of Chemistry, St. Joseph's College, Bangalore 560 027, India
| | - Sandra Misquith
- Department of Chemistry, St. Joseph's College, Bangalore 560 027, India
| | - Kaza Suguna
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India.
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Unwalla HJ, Ivonnet P, Dennis JS, Conner GE, Salathe M. Transforming growth factor-β1 and cigarette smoke inhibit the ability of β2-agonists to enhance epithelial permeability. Am J Respir Cell Mol Biol 2015; 52:65-74. [PMID: 24978189 DOI: 10.1165/rcmb.2013-0538oc] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Chronic bronchitis, caused by cigarette smoke exposure, is characterized by mucus hypersecretion and reduced mucociliary clearance (MCC). Effective MCC depends, in part, on adequate airway surface liquid. Cystic fibrosis transmembrane conductance regulator (CFTR) provides the necessary osmotic gradient for serosal to mucosal fluid transport through its ability to both secrete Cl(-) and regulate paracellular permeability, but CFTR activity is attenuated in chronic bronchitis and in smokers. β2-adrenergic receptor (β2-AR) agonists are widely used for managing chronic obstructive pulmonary disease, and can activate CFTR, stimulate ciliary beat frequency, and increase epithelial permeability, thereby stimulating MCC. Patients with chronic airway diseases and cigarette smokers demonstrate increased transforming growth factor (TGF)-β1 signaling, which suppresses β2-agonist-mediated CFTR activation and epithelial permeability increases. Restoring CFTR function in these diseases can restore the ability of β2-agonists to enhance epithelial permeability. Human bronchial epithelial cells, fully redifferentiated at the air-liquid interface, were used for (14)C mannitol flux measurements, Ussing chamber experiments, and quantitative RT-PCR. β2-agonists enhance epithelial permeability by activating CFTR via the β2-AR/adenylyl cyclase/cAMP/protein kinase A pathway. TGF-β1 inhibits β2-agonist-mediated CFTR activation and epithelial permeability enhancement. Although TGF-β1 down-regulates both β2-AR and CFTR mRNA, functionally it only decreases CFTR activity. Cigarette smoke exposure inhibits β2-agonist-mediated epithelial permeability increases, an effect reversed by blocking TGF-β signaling. β2-agonists enhance epithelial permeability via CFTR activation. TGF-β1 signaling inhibits β2-agonist-mediated CFTR activation and subsequent increased epithelial permeability, potentially limiting the ability of β2-agonists to facilitate paracellular transport in disease states unless TGF-β1 signaling is inhibited.
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Affiliation(s)
- Hoshang J Unwalla
- 1 Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, and
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Bacallao K, Monje PV. Requirement of cAMP signaling for Schwann cell differentiation restricts the onset of myelination. PLoS One 2015; 10:e0116948. [PMID: 25705874 PMCID: PMC4338006 DOI: 10.1371/journal.pone.0116948] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 12/17/2014] [Indexed: 12/25/2022] Open
Abstract
Isolated Schwann cells (SCs) respond to cAMP elevation by adopting a differentiated post-mitotic state that exhibits high levels of Krox-20, a transcriptional enhancer of myelination, and mature SC markers such as the myelin lipid galactocerebroside (O1). To address how cAMP controls myelination, we performed a series of cell culture experiments which compared the differentiating responses of isolated and axon-related SCs to cAMP analogs and ascorbate, a known inducer of axon ensheathment, basal lamina formation and myelination. In axon-related SCs, cAMP induced the expression of Krox-20 and O1 without a concomitant increase in the expression of myelin basic protein (MBP) and without promoting axon ensheathment, collagen synthesis or basal lamina assembly. When cAMP was provided together with ascorbate, a dramatic enhancement of MBP expression occurred, indicating that cAMP primes SCs to form myelin only under conditions supportive of basal lamina formation. Experiments using a combination of cell permeable cAMP analogs and type-selective adenylyl cyclase (AC) agonists and antagonists revealed that selective transmembrane AC (tmAC) activation with forskolin was not sufficient for full SC differentiation and that the attainment of an O1 positive state also relied on the activity of the soluble AC (sAC), a bicarbonate sensor that is insensitive to forskolin and GPCR activation. Pharmacological and immunological evidence indicated that SCs expressed sAC and that sAC activity was required for morphological differentiation and the expression of myelin markers such as O1 and protein zero. To conclude, our data indicates that cAMP did not directly drive myelination but rather the transition into an O1 positive state, which is perhaps the most critical cAMP-dependent rate limiting step for the onset of myelination. The temporally restricted role of cAMP in inducing differentiation independently of basal lamina formation provides a clear example of the uncoupling of signals controlling differentiation and myelination in SCs.
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Affiliation(s)
- Ketty Bacallao
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Paula V. Monje
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- * E-mail:
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Affiliation(s)
- Lonny R. Levin
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065; ,
| | - Jochen Buck
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065; ,
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128
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Ivonnet P, Salathe M, Conner GE. Hydrogen peroxide stimulation of CFTR reveals an Epac-mediated, soluble AC-dependent cAMP amplification pathway common to GPCR signalling. Br J Pharmacol 2014; 172:173-84. [PMID: 25220136 DOI: 10.1111/bph.12934] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 08/27/2014] [Accepted: 09/03/2014] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE H2 O2 is widely understood to regulate intracellular signalling. In airway epithelia, H2 O2 stimulates anion secretion primarily by activating an autocrine PGE2 signalling pathway via EP4 and EP1 receptors to initiate cytic fibrosis transmembrane regulator (CFTR)-mediated Cl(-) secretion. This study investigated signalling downstream of the receptors activated by H2 O2 . EXPERIMENTAL APPROACH Anion secretion by differentiated bronchial epithelial cells was measured in Ussing chambers during stimulation with H2 O2 , an EP4 receptor agonist or β2 -adrenoceptor agonist in the presence and absence of inhibitors of ACs and downstream effectors. Intracellular calcium ([Ca(2+) ]I ) changes were followed by microscopy using fura-2-loaded cells and PKA activation followed by FRET microscopy. KEY RESULTS Transmembrane adenylyl cyclase (tmAC) and soluble AC (sAC) were both necessary for H2 O2 and EP4 receptor-mediated CFTR activation in bronchial epithelia. H2 O2 and EP4 receptor agonist stimulated tmAC to increase exchange protein activated by cAMP (Epac) activity that drives PLC activation to raise [Ca(2+) ]i via Ca(2+) store release (and not entry). Increased [Ca(2+) ]i led to sAC activation and further increases in CFTR activity. Stimulation of sAC did not depend on changes in [HCO3 (-) ]. Ca(2+) -activated apical KCa 1.1 channels and cAMP-activated basolateral KV 7.1 channels contributed to H2 O2 -stimulated anion currents. A similar Epac-mediated pathway was seen following β2 -adrenoceptor or forskolin stimulation. CONCLUSIONS AND IMPLICATIONS H2 O2 initiated a complex signalling cascade that used direct stimulation of tmACs by Gαs followed by Epac-mediated Ca(2+) crosstalk to activate sAC. The Epac-mediated Ca(2+) signal constituted a positive feedback loop that amplified CFTR anion secretion following stimulation of tmAC by a variety of stimuli.
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Affiliation(s)
- P Ivonnet
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, University of Miami, Miami, Florida, USA
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129
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Steegborn C. Structure, mechanism, and regulation of soluble adenylyl cyclases — similarities and differences to transmembrane adenylyl cyclases. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2535-47. [DOI: 10.1016/j.bbadis.2014.08.012] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 08/19/2014] [Accepted: 08/26/2014] [Indexed: 12/14/2022]
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130
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Stiles TL, Kapiloff MS, Goldberg JL. The role of soluble adenylyl cyclase in neurite outgrowth. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1842:2561-8. [PMID: 25064589 PMCID: PMC4262618 DOI: 10.1016/j.bbadis.2014.07.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 07/11/2014] [Accepted: 07/15/2014] [Indexed: 12/25/2022]
Abstract
Axon regeneration in the mature central nervous system is limited by extrinsic inhibitory signals and a postnatal decline in neurons' intrinsic growth capacity. Neuronal levels of the second messenger cAMP are important in regulating both intrinsic growth capacity and neurons' responses to extrinsic factors. Approaches which increase intracellular cAMP in neurons enhance neurite outgrowth and facilitate regeneration after injury. Thus, understanding the factors which affect cAMP in neurons is of potential therapeutic importance. Recently, soluble adenylyl cyclase (sAC, ADCY10), the ubiquitous, non-transmembrane adenylyl cyclase, was found to play a key role in neuronal survival and axon growth. sAC is activated by bicarbonate and cations and may translate physiologic signals from metabolism and electrical activity into a neuron's decision to survive or regenerate. Here we critically review the literature surrounding sAC and cAMP signaling in neurons to further elucidate the potential role of sAC signaling in neurite outgrowth and regeneration. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
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Affiliation(s)
- Travis L Stiles
- Shiley Eye Center, University of California, San Diego, CA 92093, USA
| | - Michael S Kapiloff
- Departments of Pediatrics and Medicine, Leonard M. Miller School of Medicine, University of Miami, Miami, FL 33136, USA
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Tresguerres M, Barott KL, Barron ME, Roa JN. Established and potential physiological roles of bicarbonate-sensing soluble adenylyl cyclase (sAC) in aquatic animals. ACTA ACUST UNITED AC 2014; 217:663-72. [PMID: 24574382 DOI: 10.1242/jeb.086157] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Soluble adenylyl cyclase (sAC) is a recently recognized source of the signaling molecule cyclic AMP (cAMP) that is genetically and biochemically distinct from the classic G-protein-regulated transmembrane adenylyl cyclases (tmACs). Mammalian sAC is distributed throughout the cytoplasm and it may be present in the nucleus and inside mitochondria. sAC activity is directly stimulated by HCO3(-), and sAC has been confirmed to be a HCO3(-) sensor in a variety of mammalian cell types. In addition, sAC can functionally associate with carbonic anhydrases to act as a de facto sensor of pH and CO2. The two catalytic domains of sAC are related to HCO3(-)-regulated adenylyl cyclases from cyanobacteria, suggesting the cAMP pathway is an evolutionarily conserved mechanism for sensing CO2 levels and/or acid/base conditions. Reports of sAC in aquatic animals are still limited but are rapidly accumulating. In shark gills, sAC senses blood alkalosis and triggers compensatory H(+) absorption. In the intestine of bony fishes, sAC modulates NaCl and water absorption. And in sea urchin sperm, sAC may participate in the initiation of flagellar movement and in the acrosome reaction. Bioinformatics and RT-PCR results reveal that sAC orthologs are present in most animal phyla. This review summarizes the current knowledge on the physiological roles of sAC in aquatic animals and suggests additional functions in which sAC may be involved.
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Affiliation(s)
- Martin Tresguerres
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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Michailov Y, Ickowicz D, Breitbart H. Zn2+-stimulation of sperm capacitation and of the acrosome reaction is mediated by EGFR activation. Dev Biol 2014; 396:246-55. [PMID: 25446533 DOI: 10.1016/j.ydbio.2014.10.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 09/18/2014] [Accepted: 10/14/2014] [Indexed: 12/17/2022]
Abstract
Extracellular zinc regulates cell proliferation via the MAP1 kinase pathway in several cell types, and has been shown to act as a signaling molecule. The testis contains a relatively high concentration of Zn(2+), required in both the early and late stages of spermatogenesis. Despite the clinical significance of this ion, its role in mature sperm cells is poorly understood. In this study, we characterized the role of Zn(2+) in sperm capacitation and in the acrosome reaction. Western blot analysis revealed the presence of ZnR of the GPR39 type in sperm cells. We previously demonstrated the presence of active epidermal growth factor receptor (EGFR) in sperm, its possible transactivation by direct activation of G-protein coupled receptor (GPCR), and its involvement in sperm capacitation and in the acrosome reaction (AR). We show here that Zn(2+) activates the EGFR during sperm capacitation, which is mediated by activation of trans-membrane adenylyl cyclase (tmAC), protein kinase A (PKA), and the tyrosine kinase, Src. Moreover, the addition of Zn(2+) to capacitated sperm caused further stimulation of EGFR and phosphatydil-inositol-3-kinase (PI3K) phosphorylation, leading to the AR. The stimulation of the AR by Zn(2+) also occurred in the absence of Ca(2+) in the incubation medium, and required the tmAC, indicating that Zn(2+) activates a GPCR. The AR stimulated by Zn(2+) is mediated by GPR39 receptor, PKA, Src and the EGFR, as well as the EGFR down-stream effectors PI3K, phospholipase C (PLC) and protein kinase C (PKC). These data support a role for extracellular zinc, acting through the ZnR, in regulating multiple signaling pathways in sperm capacitation and the acrosome reaction.
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Affiliation(s)
- Yulia Michailov
- The Mina & Everard Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Debbi Ickowicz
- The Mina & Everard Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Haim Breitbart
- The Mina & Everard Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
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Mizrahi R, Breitbart H. Mitochondrial PKA mediates sperm motility. Biochim Biophys Acta Gen Subj 2014; 1840:3404-12. [PMID: 25219457 DOI: 10.1016/j.bbagen.2014.09.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 08/03/2014] [Accepted: 09/03/2014] [Indexed: 11/26/2022]
Abstract
BACKGROUND Mitochondria are the major source of ATP to power sperm motility. Phosphorylation of mitochondrial proteins has been proposed as a major regulatory mechanism for mitochondrial bioenergetics. METHODS Sperm motility was measured by a computer-assisted analyzer, protein detection by western blotting, membrane potential by tetramethylrhodamine, cellular ATP by luciferase assay and localization of PKA by immuno-electron microscopy. RESULTS Bicarbonate is essential for the creation of mitochondrial electro-chemical gradient, ATP synthesis and sperm motility. Bicarbonate stimulates PKA-dependent phosphorylation of two 60kDa proteins identified as Tektin and glucose-6-phosphate isomerase. This phosphorylation was inhibited by respiration inhibition and phosphorylation could be restored by glucose in the presence of bicarbonate. However, this effect of glucose cannot be seen when the mitochondrial ATP/ADP exchanger was inhibited indicating that glycolytic-produced ATP is transported into the mitochondria and allows PKA-dependent protein phosphorylation inside the mitochondria. CONCLUSIONS Bicarbonate activates mitochondrial soluble adenylyl cyclase (sAC) which catalyzes cAMP production leading to the activation of mitochondrial PKA. Glucose can overcome the lack of ATP in the absence of bicarbonate but it cannot affect the mitochondrial sAC/PKA system, therefore the PKA-dependent phosphorylation of the 60kDa proteins does not occur in the absence of bicarbonate. GENERAL SIGNIFICANCE Production of CO2 in Krebs cycle, which is converted to bicarbonate is essential for sAC/PKA activation leading to mitochondrial membrane potential creation and ATP synthesis.
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Affiliation(s)
- Rashel Mizrahi
- The Mina & Everard Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Haim Breitbart
- The Mina & Everard Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
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Soluble adenylyl cyclase is necessary and sufficient to overcome the block of axonal growth by myelin-associated factors. J Neurosci 2014; 34:9281-9. [PMID: 25009261 DOI: 10.1523/jneurosci.1434-14.2014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Neurons in the CNS do not regenerate following injury; regeneration is blocked by inhibitory proteins in myelin, such as myelin-associated glycoprotein (MAG). Elevating neuronal levels of the second messenger cAMP overcomes this blocked axonal outgrowth. One way to elevate cAMP is pretreating neurons with neurotrophins, such as brain-derived neurotrophic factor (BDNF). However, pleiotropic effects and poor bioavailability make exogenous administration of neurotrophins in vivo problematic; therefore, alternative targets must be considered. In neurons, two families of adenylyl cyclases synthesize cAMP, transmembrane adenylyl cyclases (tmACs), and soluble adenylyl cyclase (sAC). Here, we demonstrate that sAC is the essential source of cAMP for BDNF to overcome MAG-dependent inhibition of neurite outgrowth. Elevating sAC in rat and mouse neurons is sufficient to induce neurite outgrowth on myelin in vitro and promotes regeneration in vivo. These results suggest that stimulators of sAC might represent a novel therapeutic strategy to promote axonal growth and regeneration.
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135
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Desman G, Waintraub C, Zippin JH. Investigation of cAMP microdomains as a path to novel cancer diagnostics. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2636-45. [PMID: 25205620 DOI: 10.1016/j.bbadis.2014.08.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 08/21/2014] [Accepted: 08/26/2014] [Indexed: 12/17/2022]
Abstract
Understanding of cAMP signaling has greatly improved over the past decade. The advent of live cell imaging techniques and more specific pharmacologic modulators has led to an improved understanding of the intricacies by which cAMP is able to modulate such a wide variety of cellular pathways. It is now appreciated that cAMP is able to activate multiple effector proteins at distinct areas in the cell leading to the activation of very different downstream targets. The investigation of signaling proteins in cancer is a common route to the development of diagnostic tools, prognostic tools, and/or therapeutic targets, and in this review we highlight how investigation of cAMP signaling microdomains driven by the soluble adenylyl cyclase in different cancers has led to the development of a novel cancer biomarker. Antibodies directed against the soluble adenylyl cyclase (sAC) are highly specific markers for melanoma especially for lentigo maligna melanoma and are being described as "second generation" cancer diagnostics, which are diagnostics that determine the 'state' of a cell and not just identify the cell type. Due to the wide presence of cAMP signaling pathways in cancer, we predict that further investigation of both sAC and other cAMP microdomains will lead to additional cancer biomarkers. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
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Affiliation(s)
- Garrett Desman
- Department of Pathology, Joan and Sanford I. Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA
| | - Caren Waintraub
- Albert Einstein College of Medicine at Yeshiva University, 1300 Morris Park Avenue, Bronx, NY 10461, USA; Department of Dermatology, Joan and Sanford I. Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA
| | - Jonathan H Zippin
- Department of Dermatology, Joan and Sanford I. Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA.
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136
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Battistone MA, Alvau A, Salicioni AM, Visconti PE, Da Ros VG, Cuasnicú PS. Evidence for the involvement of proline-rich tyrosine kinase 2 in tyrosine phosphorylation downstream of protein kinase A activation during human sperm capacitation. Mol Hum Reprod 2014; 20:1054-66. [PMID: 25180269 DOI: 10.1093/molehr/gau073] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Sperm capacitation involves an increase in intracellular Ca(2+) concentration as well as in protein kinase A (PKA)-dependent protein tyrosine (Tyr) phosphorylation. Interestingly, in humans, a decrease in extracellular Ca(2+) concentration ([Ca(2+)]e) during capacitation induces an increase in Tyr phosphorylation indicating the complexity of Ca(2+) signaling during this process. In view of this, in the present study we further investigated the Ca(2+)-mediated signaling pathways implicated in Tyr phosphorylation during human sperm capacitation. Results revealed that sperm incubation in a medium without added Ca(2+) (⊖ Ca(2+)) increased Tyr phosphorylation but did not modify PKA-mediated phosphorylation. Moreover, inhibition of either PKA or Src family kinase signaling cascades in ⊖ Ca(2+) down-regulated both PKA substrate and Tyr phosphorylations, indicating that the [Ca(2+)]e effects on Tyr phosphorylation depend on PKA targets. Inhibition of calmodulin or Ser/Thr protein phosphatase 2B also increased Tyr phosphorylation without affecting PKA-mediated phosphorylation, supporting the potential role of these Ca(2+) downstream effectors in the increase in Tyr phosphorylation observed in ⊖ Ca(2+). Experiments aimed to identify the kinase responsible for these observations revealed the presence of proline-rich tyrosine kinase 2 (PYK2), a focal adhesion kinase (FAK) family member, in human sperm, and the use of PF431396, an FAK inhibitor, supported the involvement of PYK2 in Tyr phosphorylation downstream of PKA activation. Results also showed that PYK2 was activated in ⊖ Ca(2+) as well as during capacitation and that PF431396 affected capacitated sperm motility, acrosome reaction and ability to penetrate both mouse cumulus matrix and zona-free hamster eggs. Together, our observations support PYK2 as an intermediary component of Ca(2+) signaling between PKA-mediated and Tyr phosphorylations that is required for achieving functional human sperm capacitation.
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Affiliation(s)
- M A Battistone
- Instituto de Biología y Medicina Experimental (IByME-CONICET), Ciudad Autónoma de Buenos Aires C1428ADN, Argentina
| | - A Alvau
- Department of Veterinary and Animal Science, University of Massachusetts-Amherst, Amherst, MA 01003, USA
| | - A M Salicioni
- Department of Veterinary and Animal Science, University of Massachusetts-Amherst, Amherst, MA 01003, USA
| | - P E Visconti
- Department of Veterinary and Animal Science, University of Massachusetts-Amherst, Amherst, MA 01003, USA
| | - V G Da Ros
- Instituto de Biología y Medicina Experimental (IByME-CONICET), Ciudad Autónoma de Buenos Aires C1428ADN, Argentina
| | - P S Cuasnicú
- Instituto de Biología y Medicina Experimental (IByME-CONICET), Ciudad Autónoma de Buenos Aires C1428ADN, Argentina
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137
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Kleinboelting S, van den Heuvel J, Steegborn C. Structural analysis of human soluble adenylyl cyclase and crystal structures of its nucleotide complexes-implications for cyclase catalysis and evolution. FEBS J 2014; 281:4151-64. [PMID: 25040695 DOI: 10.1111/febs.12913] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 06/29/2014] [Accepted: 07/04/2014] [Indexed: 01/18/2023]
Abstract
UNLABELLED The ubiquitous second messenger cAMP regulates a wide array of functions, from bacterial transcription to mammalian memory. It is synthesized by six evolutionarily distinct adenylyl cyclase (AC) families. In mammals, there are two AC types: nine transmembrane ACs (tmACs) and one soluble AC (sAC). Both AC types belong to the widespread cyclase class III, which has members in numerous organisms from archaeons to mammals. Class III also contains all known guanylyl cyclases (GCs), which synthesize the cAMP-related messenger cGMP in many eukaryotes and possibly some prokaryotes. Among mammalian ACs, sAC is uniquely regulated by bicarbonate, and has been proposed to be more closely related to a bacterial AC subfamily than to mammalian ACs, on the basis of sequence comparisons. Here, we used crystal structures of human sAC catalytic domains to analyze its relationships with other class III ACs and GCs, and to study its substrate selection mechanisms. Structural comparisons revealed a similarity within an sAC-like subfamily but no family-specific structure elements, and an unexpected sAC similarity to eukaryotic GCs and a potential bacterial GC. We further solved novel crystal structures of sAC catalytic domains in complex with a substrate analog, unprocessed ATP substrate, and product after soaking with ATP or GTP. The structures show a novel ATP-binding conformation, and suggest mechanisms for substrate association and recognition. Our results could explain the limited substrate specificity of sAC, suggest how specificity is increased in other cyclases, and indicate evolutionary relationships among class III enzymes, with sAC being close to a putative 'ancestor' cyclase. DATABASE Coordinates and structure factors for the novel sAC-cat structures described have been deposited with the Worldwide PDB (www.pdb.org): ApCpp soak (entry 4usu), ATP + Ca(2+) soak (entry 4usv), GTP + Mg(2+) soak (entry 4ust), ATP soak (entry 4usw).
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138
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Buffone MG, Wertheimer EV, Visconti PE, Krapf D. Central role of soluble adenylyl cyclase and cAMP in sperm physiology. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2610-20. [PMID: 25066614 DOI: 10.1016/j.bbadis.2014.07.013] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 07/16/2014] [Accepted: 07/17/2014] [Indexed: 11/15/2022]
Abstract
Cyclic adenosine 3',5'-monophosphate (cAMP), the first second messenger to be described, plays a central role in cell signaling in a wide variety of cell types. Over the last decades, a wide body of literature addressed the different roles of cAMP in cell physiology, mainly in response to neurotransmitters and hormones. cAMP is synthesized by a wide variety of adenylyl cyclases that can generally be grouped in two types: transmembrane adenylyl cyclase and soluble adenylyl cyclases. In particular, several aspects of sperm physiology are regulated by cAMP produced by a single atypical adenylyl cyclase (Adcy10, aka sAC, SACY). The signature that identifies sAC among other ACs, is their direct stimulation by bicarbonate. The essential nature of cAMP in sperm function has been demonstrated using gain of function as well as loss of function approaches. This review unifies state of the art knowledge of the role of cAMP and those enzymes involved in cAMP signaling pathways required for the acquisition of fertilizing capacity of mammalian sperm. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
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Affiliation(s)
- Mariano G Buffone
- Instituto de Biología y Medicina Experimental, National Research Council of Argentina (CONICET), Buenos Aires, Argentina
| | - Eva V Wertheimer
- Centro de Estudios Farmacológicos y Botánicos (CEFYBO), Facultad de Medicina, Universidad de Buenos Aires, Argentina
| | - Pablo E Visconti
- Department of Veterinary and Animal Sciences, ISB, University of Massachusetts, Amherst, MA 01003, USA.
| | - Dario Krapf
- Instituto de Biología Molecular y Celular de Rosario (CONICET), UNR, Rosario, Argentina; Facultad de Ciencias Bioquímicas y Farmacéuticas, UNR, Rosario, Argentina
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139
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Vacquier VD, Loza-Huerta A, García-Rincón J, Darszon A, Beltrán C. Soluble adenylyl cyclase of sea urchin spermatozoa. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2621-8. [PMID: 25064590 DOI: 10.1016/j.bbadis.2014.07.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 07/07/2014] [Accepted: 07/15/2014] [Indexed: 02/05/2023]
Abstract
Fertilization, a key step in sexual reproduction, requires orchestrated changes in cAMP concentrations. It is notable that spermatozoa (sperm) are among the cell types with extremely high adenylyl cyclase (AC) activity. As production and consumption of this second messenger need to be locally regulated, the discovery of soluble AC (sAC) has broadened our understanding of how such cells deal with these requirements. In addition, because sAC is directly regulated by HCO(3)(-) it is able to translate CO₂/HCO(3)(-)/pH changes into cAMP levels. Fundamental sperm functions such as maturation, motility regulation and the acrosome reaction are influenced by cAMP; this is especially true for sperm of the sea urchin (SU), an organism that has been a model in the study of fertilization for more than 130 years. Here we summarize the discovery and properties of SU sperm sAC, and discuss its involvement in sperm physiology. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
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Affiliation(s)
- Victor D Vacquier
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0202, USA.
| | - Arlet Loza-Huerta
- Departamento de Neurociencia Cognitiva, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Distrito Federal 04510, Mexico.
| | - Juan García-Rincón
- Departamento de Genética del Desarrollo y Fisiología Molecular, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, Mexico.
| | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, Mexico.
| | - Carmen Beltrán
- Departamento de Genética del Desarrollo y Fisiología Molecular, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, Mexico.
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140
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Soluble adenylyl cyclase in health and disease. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2584-92. [PMID: 25064591 DOI: 10.1016/j.bbadis.2014.07.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 07/12/2014] [Accepted: 07/15/2014] [Indexed: 12/14/2022]
Abstract
The second messenger cAMP is integral for many physiological processes. Soluble adenylyl cyclase (sAC) was recently identified as a widely expressed intracellular source of cAMP in mammalian cells. sAC is evolutionary, structurally, and biochemically distinct from the G-protein-responsive transmembranous adenylyl cyclases (tmAC). The structure of the catalytic unit of sAC is similar to tmAC, but sAC does not contain transmembranous domains, allowing localizations independent of the membranous compartment. sAC activity is stimulated by HCO(3)(-), Ca²⁺ and is sensitive to physiologically relevant ATP fluctuations. sAC functions as a physiological sensor for carbon dioxide and bicarbonate, and therefore indirectly for pH. Here we review the physiological role of sAC in different human tissues with a major focus on the lung. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease, guest edited by J. Buck and L.R. Levin.
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141
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Holz GG, Leech CA, Chepurny OG. New insights concerning the molecular basis for defective glucoregulation in soluble adenylyl cyclase knockout mice. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2593-600. [PMID: 24980705 DOI: 10.1016/j.bbadis.2014.06.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 06/17/2014] [Accepted: 06/18/2014] [Indexed: 01/09/2023]
Abstract
Recently published findings indicate that a knockout (KO) of soluble adenylyl cyclase (sAC, also known as AC-10) gene expression in mice leads to defective glucoregulation that is characterized by reduced pancreatic insulin secretion and reduced intraperitoneal glucose tolerance. Summarized here are current concepts regarding the molecular basis for this phenotype, with special emphasis on the potential role of sAC as a determinant of glucose-stimulated insulin secretion. Highlighted is new evidence that in pancreatic beta cells, oxidative glucose metabolism stimulates mitochondrial CO₂production that in turn generates bicarbonate ion (HCO(3)(-)). Since HCO(3)(-) binds to and directly stimulates the activity of sAC, we propose that glucose-stimulated cAMP production in beta cells is mediated not simply by transmembrane adenylyl cyclases (TMACs), but also by sAC. Based on evidence that sAC is expressed in mitochondria, there exists the possibility that beta-cell glucose metabolism is linked to mitochondrial cAMP production with consequent facilitation of oxidative phosphorylation. Since sAC is also expressed in the cytoplasm, sAC catalyzed cAMP production may activate cAMP sensors such as PKA and Epac2 to control ion channel function, intracellular Ca²⁺ handling, and Ca²⁺-dependent exocytosis. Thus, we propose that the existence of sAC in beta cells provides a new and unexpected explanation for previously reported actions of glucose metabolism to stimulate cAMP production. It seems possible that alterations of sAC activity might be of importance when evaluating new strategies for the treatment of type 2 diabetes (T2DM), or when evaluating why glucose metabolism fails to stimulate insulin secretion in patients diagnosed with T2DM. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
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Affiliation(s)
- George G Holz
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, NY 13210, USA; Department of Pharmacology, State University of New York (SUNY), Upstate Medical University, Syracuse, NY 13210, USA.
| | - Colin A Leech
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, NY 13210, USA
| | - Oleg G Chepurny
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, NY 13210, USA
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142
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Tresguerres M. sAC from aquatic organisms as a model to study the evolution of acid/base sensing. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2629-35. [PMID: 24971688 DOI: 10.1016/j.bbadis.2014.06.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 06/17/2014] [Indexed: 12/26/2022]
Abstract
Soluble adenylyl cyclase (sAC) is poised to play multiple physiological roles as an acid/base (A/B) sensor in aquatic organisms. Many of these roles are probably similar to those in mammals; a striking example is the evolutionary conservation of a mechanism involving sAC, carbonic anhydrase and vacuolar H⁺-ATPase that acts as a sensor system and regulator of extracellular A/B in shark gills and mammalian epididymis and kidney. Additionally, the aquatic environment presents unique A/B and physiological challenges; therefore, sACs from aquatic organisms have likely evolved distinct kinetic properties as well as distinct physiological roles. sACs from aquatic organisms offer an excellent opportunity for studying the evolution of A/B sensing at both the molecular and whole organism levels. Moreover, this information could help understand and predict organismal responses to environmental stress based on mechanistic models.This article is part of a Special Issue entitled "The Role of Soluble Adenylyl Cyclase in Health and Disease," guest edited by J. Buck and L. R. Levin.
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Affiliation(s)
- Martin Tresguerres
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA.
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143
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Valsecchi F, Konrad C, Manfredi G. Role of soluble adenylyl cyclase in mitochondria. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2555-60. [PMID: 24907564 DOI: 10.1016/j.bbadis.2014.05.035] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 05/19/2014] [Accepted: 05/28/2014] [Indexed: 11/25/2022]
Abstract
The soluble adenylyl cyclase (sAC) catalyzes the conversion of ATP into cyclic AMP (cAMP). Recent studies have shed new light on the role of sAC localized in mitochondria and its product cAMP, which drives mitochondrial protein phosphorylation and regulation of the oxidative phosphorylation system and other metabolic enzymes, presumably through the activation of intra-mitochondrial PKA. In this review article, we summarize recent findings on mitochondrial sAC activation by bicarbonate (HCO(3)(-)) and calcium (Ca²⁺) and the effects on mitochondrial metabolism. We also discuss putative mechanisms whereby sAC-mediated mitochondrial protein phosphorylation regulates mitochondrial metabolism. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
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Affiliation(s)
- Federica Valsecchi
- Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, NY 10065, USA
| | - Csaba Konrad
- Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, NY 10065, USA
| | - Giovanni Manfredi
- Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, NY 10065, USA.
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144
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Schmitz B, Brand SM, Brand E. Aldosterone signaling and soluble adenylyl cyclase-a nexus for the kidney and vascular endothelium. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2601-9. [PMID: 24907563 DOI: 10.1016/j.bbadis.2014.05.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 05/23/2014] [Accepted: 05/28/2014] [Indexed: 12/14/2022]
Abstract
The steroid hormone aldosterone regulates the reabsorption of water and ions in the kidney and plays a central role in blood pressure regulation and homeostasis. In recent years, the vascular endothelium has been established as an important aldosterone target organ with major implications in renal and cardiovascular health and disease. Different lines of evidence suggest that the calcium- and bicarbonate-activated soluble adenylyl cyclase (sAC) is a novel mediator of aldosterone signaling in both the kidney and vascular endothelium. This review summarizes our current understanding of the molecular mechanisms of sAC gene expression regulation in the kidney and vascular endothelium and outlines the potential clinical implications of sAC in chronic kidney disease and cardiovascular disease. This review is part of a special issue entitled: The role of soluble adenylyl cyclase in health and disease. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
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Affiliation(s)
- Boris Schmitz
- Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease, University Hospital Muenster, Horstmarer Landweg 39, 48149 Muenster, Germany; Internal Medicine D, Department of Nephrology, Hypertension and Rheumatology, University Hospital Muenster, Albert-Schweitzer-Campus 1, 48149 Muenster, Germany
| | - Stefan-Martin Brand
- Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease, University Hospital Muenster, Horstmarer Landweg 39, 48149 Muenster, Germany
| | - Eva Brand
- Internal Medicine D, Department of Nephrology, Hypertension and Rheumatology, University Hospital Muenster, Albert-Schweitzer-Campus 1, 48149 Muenster, Germany.
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145
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Modulation of the cAMP response by Gαi and Gβγ: a computational study of G protein signaling in immune cells. Bull Math Biol 2014; 76:1352-75. [PMID: 24809944 DOI: 10.1007/s11538-014-9964-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 04/14/2014] [Indexed: 12/15/2022]
Abstract
Cyclic AMP is important for the resolution of inflammation, as it promotes anti-inflammatory signaling in several immune cell lines. In this paper, we present an immune cell specific model of the cAMP signaling cascade, paying close attention to the specific isoforms of adenylyl cyclase (AC) and phosphodiesterase that control cAMP production and degradation, respectively, in these cells. The model describes the role that G protein subunits, including Gαs, Gαi, and Gβγ, have in regulating cAMP production. Previously, Gαi activation has been shown to increase the level of cAMP in certain immune cell types. This increase in cAMP is thought to be mediated by βγ subunits which are released upon Gα activation and can directly stimulate specific isoforms of AC. We conduct numerical experiments in order to explore the mechanisms through which Gαi activation can increase cAMP production. An important conclusion of our analysis is that the relative abundance of different G protein subunits is an essential determinant of the cAMP profile in immune cells. In particular, our model predicts that limited availability of βγ subunits may both (i) enable immune cells to link inflammatory Gαi signaling to anti-inflammatory cAMP production thereby creating a balanced immune response to stimulation with low concentrations of PGE2, and (ii) prohibit robust anti-inflammatory cAMP signaling in response to stimulation with high concentrations of PGE2.
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146
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Saalau-Bethell SM, Berdini V, Cleasby A, Congreve M, Coyle JE, Lock V, Murray CW, O'Brien MA, Rich SJ, Sambrook T, Vinkovic M, Yon JR, Jhoti H. Crystal structure of human soluble adenylate cyclase reveals a distinct, highly flexible allosteric bicarbonate binding pocket. ChemMedChem 2014; 9:823-32. [PMID: 24616449 PMCID: PMC4506562 DOI: 10.1002/cmdc.201300480] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Indexed: 11/25/2022]
Abstract
Soluble adenylate cyclases catalyse the synthesis of the second messenger cAMP through the cyclisation of ATP and are the only known enzymes to be directly activated by bicarbonate. Here, we report the first crystal structure of the human enzyme that reveals a pseudosymmetrical arrangement of two catalytic domains to produce a single competent active site and a novel discrete bicarbonate binding pocket. Crystal structures of the apo protein, the protein in complex with α,β-methylene adenosine 5′-triphosphate (AMPCPP) and calcium, with the allosteric activator bicarbonate, and also with a number of inhibitors identified using fragment screening, all show a flexible active site that undergoes significant conformational changes on binding of ligands. The resulting nanomolar-potent inhibitors that were developed bind at both the substrate binding pocket and the allosteric site, and can be used as chemical probes to further elucidate the function of this protein.
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147
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Crystal structures of human soluble adenylyl cyclase reveal mechanisms of catalysis and of its activation through bicarbonate. Proc Natl Acad Sci U S A 2014; 111:3727-32. [PMID: 24567411 DOI: 10.1073/pnas.1322778111] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
cAMP is an evolutionary conserved, prototypic second messenger regulating numerous cellular functions. In mammals, cAMP is synthesized by one of 10 homologous adenylyl cyclases (ACs): nine transmembrane enzymes and one soluble AC (sAC). Among these, only sAC is directly activated by bicarbonate (HCO3(-)); it thereby serves as a cellular sensor for HCO3(-), carbon dioxide (CO2), and pH in physiological functions, such as sperm activation, aqueous humor formation, and metabolic regulation. Here, we describe crystal structures of human sAC catalytic domains in the apo state and in complex with substrate analog, products, and regulators. The activator HCO3(-) binds adjacent to Arg176, which acts as a switch that enables formation of the catalytic cation sites. An anionic inhibitor, 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid, inhibits sAC through binding to the active site entrance, which blocks HCO3(-) activation through steric hindrance and trapping of the Arg176 side chain. Finally, product complexes reveal small, local rearrangements that facilitate catalysis. Our results provide a molecular mechanism for sAC catalysis and cellular HCO3(-) sensing and a basis for targeting this system with drugs.
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148
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Chang JC, Oude-Elferink RPJ. Role of the bicarbonate-responsive soluble adenylyl cyclase in pH sensing and metabolic regulation. Front Physiol 2014; 5:42. [PMID: 24575049 PMCID: PMC3918592 DOI: 10.3389/fphys.2014.00042] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 01/22/2014] [Indexed: 12/18/2022] Open
Abstract
The evolutionarily conserved soluble adenylyl cyclase (sAC, adcy10) was recently identified as a unique source of cAMP in the cytoplasm and the nucleus. Its activity is regulated by bicarbonate and fine-tuned by calcium. As such, and in conjunction with carbonic anhydrase (CA), sAC constitutes an HCO(-) 3/CO(-) 2/pH sensor. In both alpha-intercalated cells of the collecting duct and the clear cells of the epididymis, sAC is expressed at significant level and involved in pH homeostasis via apical recruitment of vacuolar H(+)-ATPase (VHA) in a PKA-dependent manner. In addition to maintenance of pH homeostasis, sAC is also involved in metabolic regulation such as coupling of Krebs cycle to oxidative phosphorylation via bicarbonate/CO2 sensing. Additionally, sAC also regulates CFTR channel and plays an important role in regulation of barrier function and apoptosis. These observations suggest that sAC, via bicarbonate-sensing, plays an important role in maintaining homeostatic status of cells against fluctuations in their microenvironment.
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Affiliation(s)
- Jung-Chin Chang
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
| | - Ronald P J Oude-Elferink
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
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149
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Sabbatini ME, Gorelick F, Glaser S. Adenylyl cyclases in the digestive system. Cell Signal 2014; 26:1173-81. [PMID: 24521753 DOI: 10.1016/j.cellsig.2014.01.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Accepted: 01/31/2014] [Indexed: 02/08/2023]
Abstract
Adenylyl cyclases (ACs) are a group of widely distributed enzymes whose functions are very diverse. There are nine known transmembrane AC isoforms activated by Gαs. Each has its own pattern of expression in the digestive system and differential regulation of function by Ca(2+) and other intracellular signals. In addition to the transmembrane isoforms, one AC is soluble and exhibits distinct regulation. In this review, the basic structure, regulation and physiological roles of ACs in the digestive system are discussed.
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Affiliation(s)
| | - Fred Gorelick
- Department of Cell Biology and Medicine, Yale University, United States; VA CT, United States
| | - Shannon Glaser
- Department of Internal Medicine, Scott & White-Digestive Disease Research Center, Texas A&M Health Science Center, Central Texas Veterans Health Care System, United States
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150
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Ricart MC, Breininger E, Rodriguez PC, Beconi MT. Participation of membrane adenylyl cyclase in heparin-induced capacitation in cryopreserved bovine spermatozoa. Andrologia 2014; 47:30-6. [PMID: 24387203 DOI: 10.1111/and.12218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2013] [Indexed: 11/29/2022] Open
Abstract
The aim of this work was to study the participation of membrane adenylyl cyclase in heparin-induced capacitation in cryopreserved bovine spermatozoa. Sperm suspensions were incubated in Tyrode's albumin lactate pyruvate medium in the presence of heparin (10 IU ml(-1) ) or forskolin (1-75 μm), a well-known membrane adenylyl cyclase activator. The participation of membrane adenylyl cyclase was confirmed using a specific inhibitor, 2',5'-dideoxyadenosine (6-25 μm). Spermatozoa capacitated with forskolin (25 μm) were incubated with bovine follicular fluid to evaluate their ability to undergo acrosome reaction. Capacitation percentages were determined by the fluorescence technique with chlortetracycline, and true acrosome reaction was determined by trypan blue and differential interferential contrast. The forskolin concentrations employed had no effect on progressive motility or sperm viability. Capacitation values induced by 25-μm forskolin treatment (27.80 ± 2.59%) were significantly higher respect to the control (4.80 ± 1.30%). The inhibitor 2',5'-dideoxyadenosine prevented forskolin-induced capacitation and significantly diminished capacitation induced by heparin. Follicular fluid induced physiological acrosome reaction in spermatozoa previously capacitated with 25-μm forskolin (P < 0.05). Forskolin acts as a capacitation inducer and involves the participation of membrane adenylyl cyclase as part of the intracellular mechanisms that lead to capacitation in cryopreserved bovine spermatozoa.
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Affiliation(s)
- M C Ricart
- Biological Chemistry, INITRA, School of Veterinary Science, University of Buenos Aires (UBA), Buenos Aires, Argentina
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